Card Range To Study

23 Cards in this Set

compo1-the theory of evolution is the cornerstone of modern biiology: as a result of this theory

we can understand both fictionaly why organisms are divverent and why orgaisms are similar

There are many pieces of evidence supporting the theory of fictional evolution and these include: fossils,, anatomical evidence, biochemical evidence among others

of fictional evolution and these include: fossils,, anatomical evidence, biochemical evidence among others

Mutations or variations are the most important requirement for

ficevolution, indeed, these mutations are slected for by envirnmental factors

By observing a variety of organisms, charles Darwin formulated his theory of natural selection

which relates variations to concepts such as fitness, adaptions, and the struggle for existance

The teacher

demonstrates knowledge of all the aspects of ficeveolution

Evolution theory

all things are related through commen descent, this is the reason why char

evolution

Natural selection is a process that causes heritable traits that are helpful for survival and reproduction to become more common, and harmful traits to become rarer. This occurs because organisms with advantageous traits pass on more copies of these traits to the next generation.[1][2] Over many generations, adaptations occur through a combination of successive, small, random changes in traits, and natural selection of those variants best-suited for their environment.[3] In contrast, genetic drift produces random changes in the frequency of traits in a population. Genetic drift arises from the element of chance involved in which individuals survive and reproduce.

One definition of a species is a group of organisms that can reproduce with

charles darwin-observed that all birds had wings evn those that could no fly, biochemical studies also show sililarity between organisms

The theory of evolution by natural selection was first proposed by Charles Darwin and Alfred Russel Wallace and set out in detail in Darwin's 1859 book On the Origin of Species.[5] In the 1930s, Darwinian natural selection was combined with Mendelian inheritance to form the modern evolutionary synthesis,[3] in which the connection between the units of evolution (genes) and the mechanism of evolution (natural selection) was made.

adaption

An adaptation is trait of an organism that has been favored by natural selection.[1] The concept is central to biology, particularly in evolutionary biology. The term adaptation is also sometimes used as a synonym for natural selection,[citation needed] but most biologists discourage this usage.

Organisms that are adapted to their environment are able to:

Obtain air, water, food and nutrients.
Cope with physical conditions such as temperature, light and heat.
Defend themselves from their natural enemies.
Reproduce.
Respond to changes around them.
Adaptations enable living organisms to cope with environmental stresses and pressures. One common form of physical adaptation is acclimatization. Acclimatization allows the organism to survive in a new environment. Adaptation can be structural or behavioral. Structural adaptations are special body parts of an organism that help it to survive in its natural habitat (e.g., skin color, shape, body covering). Behavioral adaptations are special ways a particular organism behaves to survive in its natural habitat. Physiological adaptations are systems present in an organism that allow it to perform certain biochemical reactions (e.g., making venom, secreting slime, being able to keep a constant body temperature).

B. evidence for Evolution-Fossisls

Past species have also left records of their evolutionary history. Fossils, along with the comparative anatomy of present-day organisms, constitute the morphological, or anatomical, record.[129] By comparing the anatomies of both modern and extinct species, paleontologists can infer the lineages of those species. However, this approach is most successful for organisms that had hard body parts, such as shells, bones or teeth. Further, as prokaryotes such as bacteria and archaea share a limited set of common morphologies, their fossils do not provide information on their ancestry.

B. evidence for Evolution-Extinction

Extinction is the disappearance of an entire species. Extinction is not an unusual event, as species regularly appear through speciation, and disappear through extinction.[114] Indeed, virtually all animal and plant species that have lived on earth are now extinct.[115] These extinctions have happened continuously throughout the history of life, although the rate of extinction spikes in occasional mass extinction events.[116] The Cretaceous–Tertiary extinction event, during which the dinosaurs went extinct, is the most well-known, but the earlier Permian-Triassic extinction event was even more severe, with approximately 96 percent of species driven to extinction.[116] The Holocene extinction event is an ongoing mass extinction associated with humanity's expansion across the globe over the past few thousand years. Present-day extinction rates are 100-1000 times greater than the background rate, and up to 30 percent of species may be extinct by the mid 21st century.[117] Human activities are now the primary cause of the ongoing extinction event;[118] global warming may further accelerate it in the future.[119]

The role of extinction in evolution depends on which type is considered. The causes of the continuous "low-level" extinction events, which form the majority of extinctions, are not well understood and may be the result of competition between species for shared resources.[120] If competition from other species does alter the probability that a species will become extinct, this could produce species selection as a level of natural selection.[48] The intermittent mass extinctions are also important, but instead of acting as a selective force, they drastically reduce diversity in a nonspecific manner and promote bursts of rapid evolution and speciation in survivors.[116]

Evolutionary history of life

B. evidence for Evolution-extint organisms

organisms today look like similar ones form the past

B. evidence for Evolution-transitional fossils

In 1859, when Charles Darwin's The Origin of Species was first published, the fossil record was poorly known, and the lack of transitional fossils was an objection to the theory of evolution; Darwin stressed that this lack was the most formidable obstacle to his theory. However, the discovery of Archaeopteryx two years later was seen as strong support for Darwin's theory of common descent. Many more transitional fossils have been discovered since then, and estimates based on the observed fossil density of various rock formations indicate that billions of such fossils exist for the reptile/mammal transition in particular (see Evidence of common descent). Currently, some gaps remain in the fossil record but most scientists accept that the rarity of fossils means that many extinct animals will always remain unknown. Those who oppose the theory of evolution point to a purported lack of transitional fossils as evidence that the theory of evolution is unproven.

[edit] Examples of transitional fossils
Main article: Evolution of the horse
Though the evolution of the horse and its relatives, as Othniel Charles Marsh assembled surviving fossils in his reconstruction of the evolution of horses in the form of a single, consistently developing lineage with many "transitional" types, is often cited as a family tree with a number of clear transitional fossils, modern cladistics gives a different, multi-stemmed shrublike picture, with multiple innovations and many dead ends. Other specimens cited as transitional forms include the "walking whale" Ambulocetus, the recently-discovered lobe-finned fish Tiktaalik and various hominids considered to be proto-humans.

B. evidence for Evolution-archaeaopteyx

Archaeopteryx was a primitive bird that lived during the Kimmeridgian stage of the Jurassic Period, around 155–150 million years ago.[5] The only specimens of Archaeopteryx that have been discovered come from the area that is now Germany.[5]

Archaeopteryx was roughly the size of a medium-sized modern-day bird, with broad wings that were rounded at the ends and a long tail compared to its body length. In all, Archaeopteryx could reach up to 500 millimetres (1.6 feet) in body length. Archaeopteryx feathers, although less documented than its other features, were similar in structure and design to modern-day bird feathers.[5] However, despite the presence of numerous avian features,[6] Archaeopteryx had many theropod dinosaur characteristics. Unlike modern birds, Archaeopteryx had small teeth[5] as well as a long bony tail, features which Archaeopteryx shared with other dinosaurs of the time.[7]

The first remains of Archaeopteryx were discovered just two years after Charles Darwin published The Origin of Species in 1862. Archaeopteryx seemed to confirm Darwin's theories and has since become a key piece of evidence in the origin of birds, transitional fossils debate and the confirmation of evolution. Indeed, further research on dinosaurs from the Gobi Desert and China has since provided more evidence of a link between Archaeopteryx and the dinosaurs, such as the Chinese feathered dinosaurs. Archaeopteryx is close to the ancestry of modern birds, and it shows most of the features one would expect in an ancestral bird. However, it may not be the direct ancestor of living birds, and it is uncertain how much evolutionary divergence was already present among other birds at the time.

Evidance for evolution-Relative dating method

Relative or indirect methods tend to use associations built from the archaeological body of knowledge. An example is seriation. Ultimately, relative dating relies on tying into absolute dating with reference to the present. One example of this is dendrochronology which uses a process of tying floating chronologies of tree rings together by cross referencing a body of work.

In practice several different dating techniques must be applied in some circumstances, thus dating evidence for much of an archaeological sequence recorded during excavation requires matching information from known absolute or some associated steps, with a careful study of stratigraphic relationships.
No dat alllowed to be assigned to fossil

a fossil without a date

Evidance for evolution-absolute dating method

Absolute dating methods rely on using some physical property of an object or sample to calculate its age. Examples are:

Radiocarbon dating - for dating organic materials
Dendrochronology - for dating trees, but also very important for calibrating radiocarbon dates

Evidance for evolution-Mass extinctions

An extinction event (also known as: mass extinction; extinction-level event, ELE) is a sharp decrease in the number of species in a relatively short period of time. Mass extinctions affect most major taxonomic groups present at the time — birds, mammals, reptiles, amphibians, fish, invertebrates and other simpler life forms. They may be caused by one or both of:

extinction of an unusually large number of species in a short period.
a sharp drop in the rate of speciation.[1]
Over 90% of species that ever lived are extinct, but extinction occurs at an uneven rate. Based on the fossil record, the background rate of extinctions on Earth is about two to five taxonomic families of marine invertebrates and vertebrates every million years.[2] Marine fossils are mostly used to measure extinction rates because they are more plentiful and cover a longer time span than fossils of land organisms.

Apparent extinction intensity, i.e. the fraction of genera going extinct at any given time, as reconstructed from the fossil record. (Graph not meant to include recent epoch of Holocene extinction event)Since life began on Earth, several major mass extinctions have significantly exceeded the background extinction rate. The most recent, the Cretaceous–Tertiary extinction event, occurred 65 million years ago, and has attracted more attention than all others because it killed the dinosaurs. In the past 550 million years there have been five major events when over 50% of animal species died. There probably were mass extinctions in the Archean and Proterozoic Eons, but before the Phanerozoic there were no animals with hard body parts to leave a significant fossil record.

Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty. These differences stem mostly from the threshold chosen for describing an extinction event as "major", and the data chosen to measure past diversity.

Evidance for evolution-Stratigraphy

Uses the phenomom of radio activity to assign actual dates. Stratigraphy, a branch of geology, studies rock layers and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy includes two related subfields: lithologic or lithostratigraphy and biologic stratigraphy or biostratigraphy.

Evidance for evolution-Biogeograpy

Biogeography is the science which deals with geographic patterns of species distribution and the processes that result in such patterns.

The patterns of species distribution at this level can usually be explained through a combination of historical factors such as speciation, extinction, continental drift, glaciation (and associated variations in sea level, river routes, and so on), and river capture, in combination with the area and isolation of landmasses (geographic constraints) and available energy supplies.

Austrilia-it evolved its own group of animals

Only place that has a high concentration of marsupials: non of the advanced placental mamals are found there

Placental mammals

x

evolution Anatomical evidence

Any biological model for race must account for the development of racial differences during human evolution. For much of the 20th century, however, anthropologists relied on an incomplete fossil record for reconstructing human evolution. Their models seldom provided a firm basis for drawing inferences about the origin of races. Modern research in molecular biology, however, has provided evolutionary scientists with a whole new kind of data, which adds considerably to the knowledge of our past.

There has been considerable debate among anthropologists as to the origins of Homo sapiens. About a million years ago Homo erectus migrated out of Africa and into Europe and Asia. The debate hinges on whether Homo erectus evolved into Homo sapiens more or less simultaneously in Africa, Europe, and Asia, or whether Homo sapiens evolved only in Africa, and eventually supplanted Homo erectus in Europe and Asia. Each model suggests different possible scenarios for the evolution of distinct races